Insects In General Research Articles

Leaffooted Bugs: Insect Pest Species of Growing Concern for Agriculture.

Leptoglossus (Hemiptera: Coreidae) are a diverse genus of phytophagous insects. Literature regarding Leptoglossus has increased as species are identified as emerging agricultural pests or reported outside of their native range. Within Leptoglossus, five species dominate the literature and are known pests and vectors of plant pathogenic microbes in several major crops. Despite the increasing profile of Leptoglossus, current monitoring and management methods rely primarily on visual inspection, and semiochemical tools have yet to be developed. This Perspective identifies and discusses gaps in the Leptoglossus literature as well as areas of research needed for the development of effective tools for monitoring insect populations and enabling informed pest-management practices.

RNAi silencing CHS1 gene shortens the mortality time of Plutella xylostella feeding Bt-transgenic Brassica napus.

Insect-resistance genetically modified (GM) plants derived from Bacillus thuringiensis (Bt) have been cultivated to control pests, but continuous cultivation of Bt-transgenic plants at large-scale regions leads to the resistance evolution of target insects to transgenic plants. RNA interference (RNAi) technology is considered an effective strategy in delaying the resistance evolution of target insects. We here developed a single transgenic oilseed rape (Brassica napus) line with hairpin RNA of the chitin-synthase 1 gene (CHS1) of Plutella xylostella (hpPxCHS1) and a pyramid transgenic B. napus line harboring hpPxCHS1 and Bt gene (Cry1Ac). Escherichia coli HT115 delivered hpPxCHS1 showed negative effects on the growth of P. xylostella. The single transgenic and pyramid transgenic B. napus significantly reduced the larval weight and length of P. xylostella and increased its lethality rate, with down-regulation expression of the PxCHS1 gene in insects. Compared to Bt-transgenic B. napus, pyramid-transgenic B. napus shorted the mortality time of P. xylostella, indicating that RNAi technology synergistic with Bt protein improves the effectiveness of controlling target insects. Our results proved that RNAi can delay the resistance evolution of target insects to Bt-transgenic plants. © 2024 Society of Chemical Industry.

Identification and function of the Pax gene Bmgsb in the silk gland of Bombyx mori.

Paired box (Pax) genes are highly conserved throughout evolution, and the Pax protein is an important transcription factor of embryonic development. The Pax gene Bmgsb is expressed in the silk glands of silkworm, but its biological functions remain unclear. This study aimed to investigate the expression pattern of Bmgsb in the silk gland and explore its functions using RNA interference (RNAi). Here, we identified eight Pax genes in Bombyx mori. Phylogenetic analysis showed that the B. mori Pax genes were highly homologous to the Pax genes in other insects and highly evolutionarily conserved. The tissue expression profile showed that Bmgsb was expressed in the anterior silk gland and anterior part of the middle silk gland (AMSG). RNAi of Bmgsb resulted in defective development of the AMSG, and the larvae were mostly unable to cocoon in the wandering stage. RNA-seq analysis showed that the fibroin genes fib-l, fib-h and p25, cellular heat shock response-related genes and phenol oxidase genes were considerably upregulated upon Bmgsb knockdown. Furthermore, quantitative reverse transcription-PCR results showed that the fibroin genes and ubiquitin proteolytic enzyme-related genes were significantly upregulated in the AMSG after Bmgsb knockdown. This study provides a foundation for future research on the biological functions of B. mori Pax genes. In addition, it demonstrates the important roles of Bmgsb in the transcriptional regulation of fibroin genes and silk gland development.

Mindanao broken stick insect: a new species and first country record of the genus Baculofractum Zompro, 1995 (Phasmatodea: Lonchodidae: Lonchodinae: Lonchodini) from the Philippines

Baculofractum Zompro 1995 is a genus of stick insects in the family Lonchodidae, subfamily Lonchodinae represented by three species: B. insigne, B. shelfordi, and B. williemsei, distributed in Indonesia and Malaysia. This paper reports the discovery of a new species of Baculofractum from Mt. Malimumu, Pantaron Range, Bukidnon which also represents the first record of the genus in the Philippines. The new species can be distinguished by the absence of four tubercles at the back of the head’s median ridges and its distinctly elongated operculum exceeding the end of the abdomen.

Comparative transcriptomic analysis of salivary glands between the zoophytophagous Cyrtorhinus lividipennis and the phytozoophagous Apolygus lucorum

BackgroundSaliva plays a crucial role in shaping the feeding behavior of insects, involving processes such as food digestion and the regulation of interactions between insects and their hosts. Cyrtorhinus lividipennis serves as a predominant natural enemy of rice pests, while Apolygus lucorum, exhibiting phytozoophagous feeding behavior, is a destructive agricultural pest. In this study, a comparative transcriptome analysis, incorporating the published genomes of C.lividipennis and A.lucorum, was conducted to reveal the role of salivary secretion in host adaptation.ResultsIn contrast to A.lucorum, C.lividipennis is a zoophytophagous insect. A de novo genome analysis of C.lividipennis yielded 19,706 unigenes, including 16,217 annotated ones. On the other hand, A.lucorum had altogether 20,111 annotated genes, as obtained from the published official gene set (20,353 unigenes). Functional analysis of the top 1,000 salivary gland (SG)-abundant genes in both insects revealed that the SG was a dynamically active tissue engaged in protein synthesis and secretion. Predictions of other tissues and signal peptides were compared. As a result, 94 and 157 salivary proteins were identified in C.lividipennis and A.lucorum, respectively, and were categorized into 68 and 81 orthogroups. Among them, 26 orthogroups were shared, potentially playing common roles in digestion and detoxification, including several venom serine proteases. Furthermore, 42 and 55 orthogroups were exclusive in C.lividipennis and A.lucorum, respectively, which were exemplified by a hyaluronidase in C.lividipennis that was associated with predation, while polygalacturonases in A.lucorum were involved in mesophyll-feeding patterns.ConclusionsFindings in this study provide a comprehensive insight into saliva secretions in C.lividipennis and A.lucorum via a transcriptome approach, reflecting the intricate connections between saliva secretions and feeding behaviors. It is found that conserved salivary secretions are involved in shaping the overlapping feeding patterns, while a plethora of unique salivary secretions may drive the evolution of specific feeding behaviors crucial for their survival. These results enhance our understanding of the feeding mechanisms in different insects from the perspective of saliva and contribute to future environmentally friendly pest control by utilizing predatory insects.

Hormonal control of <i>fruitless</i> expression and male sexual orientation in <i>Drosophila</i>

<p>Sex determination genes control the differentiation of gonads that synthesize and secret sex hormones to remotely control sexual development and behaviors in mammals. In contrast, sex determination genes in insects directly control sexual development and behaviors in a cell-autonomous way, which is largely independent of hormones. In this study, we find that two important hormones, juvenile hormone (JH) and 20-hydroxyecdysone (20E), oppositely regulate the dynamic expression of Fru<sup>M</sup>, the male-specific product of the sex determination gene <i>fruitless</i> in <i>Drosophila</i>. 20E signaling is essential to the high-level expression of Fru<sup>M</sup> proteins in the pupal stage, while JH suppresses larval Fru<sup>M</sup> expression through inhibiting 20E signaling. We further show that 20E signaling regulates both the development and physiological function of the male-specific P1 neurons to mediate sexual orientation in male flies. Our results demonstrate both conserved and diversified functions of hormones in sexual development and behaviors in flies and mice.</p>

Advances in CRISPR/Cas9-Based Gene Editing Technology in Mosquitoes

As global warming increases, mosquito activity areas are expanding, alongside changes in the natural environment and the misuse of insecticides, thus further increasing mosquito resistance and exposing the world to an elevated risk of mosquito-borne diseases. With advancements in gene editing technology, researchers are continually attempting to modify various mosquito genes and validate their functional roles with CRISPR-Cas9 technology. Here, we review recent applications of CRISPR-Cas9-based gene editing technology in mosquito-borne disease prevention and control, as well as mosquito population suppression, phenotyping, and resistance. We further discuss the development of new techniques, such as ReMOT Control and DIPA-CRISPR, which differ from conventional embryo microinjection and should be expanded in future insect gene editing research.

First report of two insects, Megachile sp. and Armadillidium sp., as new pests on Flemingia spp. In Thrissur, Kerala

A project entitled "Conservation of Lac Insect Genetic Resources" is underway at the Kerala Forest Research Institute (KFRI) at Peechi, Thrissur, Kerala, India. This project includes the maintenance of both a lac insect gene bank and a lac insect host plant gene bank. Two types of host plants, Flemingia semialata (F. semialata) and Flemingia macrophylla (F. macrophylla), are cultivated to support the lac insect, Kerria spp. In the month of May, it was observed that Megachile bees were cutting the leaves of F. semialata and using them to construct nests. Roly-poly (Armadillidium spp) insects were also found affecting the young leaves of seedlings of F. semialata and F. macrophylla at KFRI. These two insects, Megachile and Armadillidium, are newly reported for the first time on the plants of F. semialata and F. macrophylla in Kerala.

Analyzing the evolution of insect TMED gene and the expression pattern of silkworm TMED gene

Transmembrane emp24 domain (TMED) gene is closely related to immune response, signal transduction, growth and disease development in mammals. However, only the Drosophila TMED gene has been reported on insects. We identified the TMED family genes of silkworm, Tribolium castaneum, tobacco moth and Italian bee from their genomes, and found that the TMED family gene composition patterns of one α-class, one β-class, one δ-class and several γ-classes arose in the common ancestor of pre-divergent Hymenoptera insects, while the composition of Drosophila TMED family members has evolved in a unique pattern. Insect TMED family γ-class genes have evolved rapidly, diverging into three separate subclasses, TMED6-like, TMED5-like and TMED3-like. The TMED5-like gene was lost in Hymenoptera, duplicated in the ancestors of Lepidoptera and duplicated in Drosophila. Insect TMED protein not only has typical structural characteristics of TMED, but also has obvious signal peptide. There are seven TMED genes in silkworm, distributed in six chromosomes. One of seven is single exon and others are multi-exons. The complete open reading frame (ORF) sequences of seven TMED genes of silkworm were cloned from larval tissues and registered in GenBank database. BmTMED1, BmTMED2 and BmTMED6 were expressed in all stages and tissues of the silkworm, and all genes were expressed in the 4th and 5th instar and silk gland of the silkworm. The present study revealed the composition pattern of TMED family members, their γ class differentiation and their evolutionary history, providing a basis for further studies on TMED genes in silkworm and other insects.

Comparison of insect and human cytochrome b561 proteins: Insights into candidate ferric reductases in insects.

Cytochrome b561 (cytb561) proteins comprise a family of transmembrane oxidoreductases that transfer single electrons across a membrane. Most eukaryotic species, including insects, possess multiple cytb561 homologs. To learn more about this protein family in insects, we carried out a bioinformatics-based investigation of cytb561 family members from nine species representing eight insect orders. We performed a phylogenetic analysis to classify insect cytb561 ortholog groups. We then conducted sequence analyses and analyzed protein models to predict structural elements that may impact the biological functions and localization of these proteins, with a focus on possible ferric reductase activity. Our study revealed three ortholog groups, designated CG1275, Nemy, and CG8399, and a fourth group of less-conserved genes. We found that CG1275 and Nemy proteins are similar to a human ferric reductase, duodenal cytochrome b561 (Dcytb), and have many conserved amino acid residues that function in substrate binding in Dcytb. Notably, CG1275 and Nemy proteins contain a conserved histidine and other residues that play a role in ferric ion reduction by Dcytb. Nemy proteins were distinguished by a novel cysteine-rich cytoplasmic loop sequence. CG8399 orthologs are similar to a putative ferric reductase in humans, stromal cell-derived receptor 2. Like other members of the CYBDOM class of cytb561 proteins, these proteins contain reeler, DOMON, and cytb561 domains. Drosophila melanogaster CG8399 is the only insect cytb561 with known ferric reductase activity. Our investigation of the DOMON domain in CG8399 proteins revealed a probable heme-binding site and a possible site for ferric reduction. The fourth group includes a subgroup of proteins with a conserved "KXXXXKXH" non-cytoplasmic loop motif that may be a substrate binding site and is present in a potential ferric reductase, human tumor suppressor cytochrome b561. This study provides a foundation for future investigations of the biological functions of cytb561 genes in insects.

Dynamic gene expression of southern rice black-streaked dwarf virus during its infection in rice plants and vector insects

In this century, a disease caused by southern rice black-streaked dwarf virus (SRBSDV) has resulted in significant loss in rice production in Asia. Aside from infecting rice plants, SRBSDV is transmitted by white-backed planthopper (WBPH) in a persistent propagative manner. Recent studies showed that SRBSDV can dynamically modulate the host cells throughout the infection progress. However, the expression dynamics of the SRBSDV genes during infection remain unclear. Here we established an absolute real-time quantitative PCR method to assess the dynamic of the SRBSDV genes expression in rice plants and planthoppers. Apart from displaying the expression levels of viral genes, we discovered that the expression level of viral genes in insects significantly surpasses that in plant cells. In addition, we identified two nonstructural proteins with unknown functions that exhibit the highest expression levels in plant and insect cells, respectively, which provide possible targets for restraining the disease outbreaks.

Sex pheromone biosynthesis in the sugarcane borer Diatraea saccharalis: paving the way for biotechnological production.

The sugarcane borer Diatraea saccharalis (Lepidoptera) is a key pest on sugarcane and other grasses in the Americas. Biological control as well as insecticide treatments are used for pest management, but economic losses are still significant. The use of female sex pheromones for mating disruption or mass trapping in pest management could be established for this species, provided that economical production of pheromone is available. Combining in vivo labelling studies, differential expression analysis of transcriptome data and functional characterisation of insect genes in a yeast expression system, we reveal the biosynthetic pathway and identify the desaturase and reductase enzymes involved in the biosynthesis of the main pheromone component (9Z,11E)-hexadecadienal, and minor components hexadecanal, (9Z)-hexadecenal and (11Z)-hexadecenal. We next demonstrate heterologous production of the corresponding alcohols of the pheromone components, by expressing multiple steps of the biosynthetic pathway in yeast. Elucidation of the genetic basis of sex pheromone biosynthesis in D. saccharalis, and heterologous expression in yeast, paves the way for biotechnological production of the pheromone compounds needed for pheromone-based pest management of this species. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Efficient DIPA-CRISPR-mediated knockout of an eye pigment gene in the white-backed planthopper, Sogatella furcifera.

Although CRISPR/Cas9 has been widely used in insect gene editing, the need for the microinjection of preblastoderm embryos can preclude the technique being used in insect species with eggs that are small, have hard shells, and/or are difficult to collect and maintain outside of their normal environment. Such is the case with Sogatella furcifera, the white-backed planthopper (WBPH), a significant pest of Oryza sativa (rice) that oviposits inside rice stems. Egg extraction from the stem runs the risk of mechanical damage and hatching is heavily influenced by the micro-environment of the rice stem. To bypass these issues, we targeted embryos prior to oviposition via direct parental (DIPA)-CRISPR, in which Cas9 and single-guide RNAs (sgRNAs) for the WBPH eye pigment gene tryptophan 2,3-dioxygenase were injected into the hemocoel of adult females. Females at varying numbers of days posteclosion were evaluated to determine at what stage their oocyte might be most capable of taking up the gene-editing components. An evaluation of the offspring indicated that the highest G0 gene-edited efficacy (56.7%) occurred in females injected 2d posteclosion, and that those mutations were heritably transmitted to the G1 generation. This study demonstrates the potential utility of DIPA-CRISPR for future gene-editing studies in non-model insect species and can facilitate the development of novel pest management applications.

Exploring the Significance of Insects in Ecosystems: A Comprehensive Examination of Entomological Studies

The dynamic and expansive field of entomology is poised for transformative changes, thanks to technological advancements and the emergence of new avenues of research. Traditional methodologies like specimen collection and observation are increasingly being complemented by state-of-the-art techniques such as environmental DNA (eDNA) analysis, CRISPR genome editing, remote sensing, and artificial intelligence. The eDNA methodology, for example, offers a non-invasive approach to monitor elusive or endangered insect species, thereby enriching biodiversity databases. Genome editing technologies like CRISPR have enabled nuanced manipulation of insect genes, providing a deeper understanding of their physiology and behavior. Moreover, artificial intelligence and machine learning contribute to automated species identification and predictive modeling of insect populations, offering invaluable insights for conservation efforts. In terms of emerging fields, insect neurobiology, microbiomics, and environmental entomology are gaining prominence. Neurobiological studies are dissecting the neural substrates of insect behaviors, which not only deepen our basic biological understanding but also have implications in robotics and AI. Microbiomics explores the symbiotic relationships between insects and their microbial communities, revealing avenues for novel pest control strategies. Environmental entomology focuses on the impacts of habitat change and climate variability on insect populations, which is crucial for biodiversity conservation. Acknowledging the concerted efforts of researchers, academic institutions, and funding bodies is essential, as these stakeholders shape the field's future direction. Thus, entomology stands at the cusp of a new era, enriched by technological innovations and multidisciplinary approaches. These advancements hold the promise of significantly broadening our understanding of insects' roles in ecosystems, their adaptability, and their importance in maintaining ecological balance. This future direction not only provides exciting prospects for scientific inquiry but also brings forth substantial implications for the sustainable management of ecosystems and conservation policy.

Development of an intelligent field investigation system for Liriomyza using SeResNet-Liriomyza for accurate identification

Liriomyza (Diptera: Agromyzidae) is genus of insects found worldwide. Among the species in this genus, L. sativae, L. huidobrensis, L. trifolii, and L. bryoniae are the four most globally invasive, with L. chinensis being native to China. Real-time and accurate monitoring is a prerequisite for reducing the spread and crop damage caused by this pest. Owing to the small size of Liriomyza, specialized technicians using a microscope are needed to identify them. We developed an intelligent field investigation system to conveniently and accurately identify these five species. The system includes a portable image acquisition device based on a smartphone, a deep learning-based image recognition model for Liriomyza, and a mobile platform-based investigation application. To capture magnified images of Liriomyza, we designed a magnifying lens and a rotatable carrier assembled outside the smartphone camera. To address the problem of local blurring in images captured by smartphones, all images were sharpened to enhance their features. To accurately distinguish these five species from similar species, we developed a SeResNet-Liriomyza model, which embeds spatial feature pyramid networks (SFPN) in the SeResNet model to prevent the false positives caused by different sizes of input images and generate new feature maps favorable for classification by combining global and local image features. Compared with the excellent classification models, DenseNet-201, ResNeXt-50, MobileNet-v3, EfficientNet-B4, and ResNeSt-101, SeResNet-Liriomyza showed excellent recognition performance, with an average recognition accuracy of 99.88%. We designed and developed a mobile application (app) for the intelligent investigation of Liriomyza. The app includes functions such as intelligent investigation, intelligent recognition, a biological dictionary, and investigation result retrieval. The proposed intelligent field investigation system provides investigators with a fast, convenient, and accurate tool for investigating Liriomyza, a pest that can cause serious damage to agriculture in the field.

Expression Analysis Reveals Differentially Expressed Genes in BPH and WBPH Associated with Resistance in Rice RILs Derived from a Cross between RP2068 and TN1.

BPH (brown planthopper) and WBPH (white backed planthopper) are significant rice pests that often co-occur as sympatric species and cause substantial yield loss. Despite their genetic similarities, different host-resistance genes confer resistance against these two hoppers. The defense mechanisms in rice against these pests are complex, and the molecular processes regulating their responses remain largely unknown. This study used specific recombinant inbred lines (RILs) derived from a cross between rice varieties RP2068-18-3-5 (BPH- and WBPH-resistant) and TN1 (BPH- and WBPH-susceptible) to investigate the mechanisms of interaction between these planthoppers and their rice hosts. WBPH and BPH were allowed to feed on specific RILs, and RNA-Seq was carried out on WBPH insects. Transcriptome profiling and qRT-PCR results revealed differential expression of genes involved in detoxification, digestion, transportation, cuticle formation, splicing, and RNA processing. A higher expression of sugar transporters was observed in both hoppers feeding on rice with resistance against either hopper. This is the first comparative analysis of gene expressions in these insects fed on genetically similar hosts but with differential resistance to BPH and WBPH. These results complement our earlier findings on the differential gene expression of the same RILs (BPH- or WBPH-infested) utilized in this study. Moreover, identifying insect genes and pathways responsible for countering host defense would augment our understanding of BPH and WBPH interaction with their rice hosts and enable us to develop lasting strategies to control these significant pests.

DNA degradation in Haplaxius crudus (Hemiptera: Cixiidae) and Diaphorina citri (Hemiptera: Liviidae) on yellow sticky traps in Florida.

Lethal bronzing (LB) and huanglongbing (HLB) are harmful plant diseases causing significant economic losses in Florida agriculture. Both diseases are caused by bacteria that are transmitted by Hemipteran insect vectors. Accurate detection of pathogens within insect vectors can help provide a better understanding of disease epidemiology. Monitoring of the vector of LB is done primarily using sticky traps within palm canopies. However, it is unknown how long pathogen and vector DNA remain intact under field conditions. If significant DNA degradation takes place over the course of days or weeks, there is a possibility of false negatives occurring when detecting pathogens from these surveys. This study determined how long Haplaxius crudus Van Duzee (Hemiptera: Cixiidae) and LB DNA could remain detectable on sticky traps under field conditions in Florida in winter and summer, using PCR and qPCR. Additionally, this study compared the DNA degradation of Diaphorina citri Kuwayama (Hemiptera: Liviidae) and Candidatus Liberibacter asiaticus (CLas), the causal agent of HLB. The results showed that DNA concentration and amplification rate declined as time on sticky traps increased. Degradation varied between different target genes. The amplification rate of insect genes from sticky trap samples suggests that sticky traps should be changed weekly in summer, and every 2 wk in winter for accurate H. crudus detection. Traps should be changed every 4 days for phytoplasma detection. Traps can be changed monthly for accurate D. citri and CLas detection. Based on these results, standard monitoring protocols can be implemented to more accurately detect vectors and pathogens.

SeBLOS2 knockout via CRISPR/Cas9 leads to the loss of larval integument coloration in Spodoptera exigua (Lepidoptera: Noctuidae).

CRISPR/Cas9 technology is a precise and powerful tool for functionally exploring insect genes. The present study tested CRISPR/Cas9 as a way of undertaking effective gene mutagenesis in an important agricultural pest, the beet armyworm Spodoptera exigua. Based on a S. exigua transcriptome database, the entire complementary DNA sequence of SeBLOS2 encoding 140 amino acid residues was cloned. The gene was highly expressed in late larval stages (L3-L5). Using the CRISPR/Cas9 method, SeBLOS2 was knocked out by altering two sites in the coding region. This resulted in 70%-74% of the G0 generation (L4-L5) larvae displaying mosaic translucent integument. Four different mutations occurred at SeBLOS2-specific target sites, as demonstrated by further polymerase chain reaction-based genotypic analysis. Homozygote mutant L3 larvae were obtained in the G1 generation, with complete loss of white stripes and spots on their larval integument. These results demonstrate a crucial role of SeBLOS2 in integument pigmentation and suggest that the gene can act as a suitable nonlethal marker for functional research on genes in S. exigua and other Lepidopteran pests.

Till evolution do us part: The diversity of symbiotic associations across populations of Philaenus spittlebugs.

Symbiotic bacteria have played crucial roles in the evolution of sap-feeding insects and can strongly affect host function. However, their diversity and distribution within species are not well understood; we do not know to what extent environmental factors or associations with other species may affect microbial community profiles. We addressed this question in Philaenus spittlebugs by surveying both insect and bacterial marker gene amplicons across multiple host populations. Host mitochondrial sequence data confirmed morphology-based identification of six species and revealed two divergent clades of Philaenus spumarius. All of them hosted the primary symbiont Sulcia that was almost always accompanied by Sodalis. Interestingly, populations and individuals often differed in the presence of Sodalis sequence variants, suggestive of intra-genome 16S rRNA variant polymorphism combined with rapid genome evolution and/or recent additional infections or replacements of the co-primary symbiont. The prevalence of facultative endosymbionts, including Wolbachia, Rickettsia, and Spiroplasma, varied among populations. Notably, cytochrome I oxidase (COI) amplicon data also showed that nearly a quarter of P. spumarius were infected by parasitoid flies (Verralia aucta). One of the Wolbachia operational taxonomic units (OTUs) was exclusively present in Verralia-parasitized specimens, suggestive of parasitoids as their source and highlighting the utility of host gene amplicon sequencing in microbiome studies.

Host-Delivered RNA Interference for Durable Pest Resistance in Plants: Advanced Methods, Challenges, and Applications.

Insect-pests infestation greatly affects global agricultural production and is projected to become more severe in upcoming years. There is concern about pesticide application being ineffective due to insect resistance and environmental toxicity. Reduced effectiveness of Bt toxins also made the scientific community shift toward alternative strategies to control devastating agricultural pests. With the advent of host-delivered RNA interference, also known as host-induced gene silencing, targeted insect genes have been suppressed through genetic engineering tools to deliver a novel insect-pest resistance strategy for combating a number of agricultural pests. This review recapitulates the possible mechanism of host-delivered RNA interference (HD-RNAi), in particular, the silencing of target genes of insect-pests. We emphasize the development of the latest strategies against evolving insect targets including designing of artificial microRNAs, vector constructs, and the benefit of using plastid transformation to transform target RNA-interfering genes. Advantages of using HD-RNAi over other small RNA delivery modes and also the supremacy of HD-RNAi over the CRISPR-Cas system particularly for insect resistance have been described. However, the broader application of this technology is restricted due to its several limitations. Using artificial miRNA designs, the host-delivered RNAi + Bt combinatorial approach and chloroplast transformation can overcome limitations of RNAi. With careful design and delivery approaches, RNAi promises to be extremely valuable and effectiveplant protection strategy toattain durable insect-pest resistance in crops.